1. Field of the Invention
This invention relates generally to antimicrobial peptides, and, more specifically, to peptides designated bovine granulocyte peptide -A (BGP-A), bovine granulocyte peptide -A-amide (BGP-A-amide), murine granulocyte peptide -A(MGP-A) and murine granulocyte peptide -A-amide (MGP-A-amide) and methods of uses thereof.
2. Background of the Invention
The cytoplasmic granules of polymorphonuclear leukocytes (neutrophils, granulocytes, PMNs) contain antimicrobial peptides that allow these cells to inactivate ingested microbial targets by mechanisms considered xe2x80x9coxygen independentxe2x80x9d (Lehrer, R. I. et al., Blood 76:2169-2181. 1990). These granule proteins constitute an antimicrobial arsenal that includes defensins (Selsted, M. E., et al., Trends in Cell Biology 5:114-119, 1995), xcex2-defensins (Selsted, M. E., et al., J. Biol. Chem. 268:6641-6648, 1993), indolicidin (Selsted, M. E., et al., J. Biol. Chem.267:4292-4295, 1992), and other broad spectrum antibiotic peptides that are released into the phagosome during phagolysosome fusion. To date, members of the defensin family have been isolated from neutrophils of human (Ganz, T., et al., J. Clin. Invest. 76:1427-1435, 1985), rabbit (Selsted, M. E., et al., J. Biol. Chem. 260:4579-4584, 1985), rat (Eisenhauer, P., et al., Immun. 58:3899-3902, 1990), and guinea pig origin (Selsted, M. E., et al., Infect. Immun. 55:2281-2286, 1987), and most recently from the Paneth cells of mouse small intestine (Selsted, M. E., et al., J. Cell Biol. 118:929-936, 1992). xcex2-defensins have been isolated from the large granules of bovine neutrophils (Selsted, M. E., et al., J. Biol. Chem.268:6641-6648, 1993), bovine tracheal epithelium (Diamond, G. M., et al., Proc. Natl. Acad Sci. USA 88:3952-3956, 1991), and human plasma (Bensch, K. W., et al., FEBS Lett.368:331-335), and indolicidin is a component of the large granules of bovine PMN (Van Abel, R. J., et al., Int. J. Peptide Protein 45:401-409, 1995).
The unique features of ruminant granulocytes were first described by Gennaro and Baggiolini and coworkers (Baggiolini, M., et al., Lab. Invest. 52:151-158, 1985; Gennaro, R., et al, J. Cell Biol. 96:1651-1661, 1983) who demonstrated that neutrophils of cattle, goats, sheep, and ibex are endowed with many unusually large cytoplasmic granules that are distinct from the classical azurophil and specific granules. Subsequent studies established that most of the antibacterial peptides of bovine neutrophils are contained in these unique organelles. Romeo and Gennarro have demonstrated that the large granules of bovine neutrophils contain potent microbicidal peptides that are structurally distinct from defensins (Gennaro, R., et al, Infect. Immun. 57:3142-3146, 1989; Romeo, D., et al, J. Biol. Chem. 263:9573-9575, 1988).These include three arginine-rich peptides, termed bactenecins, which efficiently kill several gram positive and gram negative bacteria in vitro. Recently, the isolation and characterization of a novel tridecapeptide amide, indolicidin, from bovine neutrophils was reported (Selsted, M. E., et al, J. Biol. Chem. 267:4292-4295, 1992). This cationic peptide was shown to be unusually rich in tryptophan, and to have potent bactericidal activity against E. coli and S. aureus. More recently the isolation of 13 xcex2-defensins from bovine neutrophils demonstrated that these peptides are covalently dissimilar to defensins, while possessing a similar folded conformation (Selsted, M. E., et al., J. Biol. Chem. 268:6641-6648, 1993).
The present invention provides peptides useful as antimicrobial agents. The invention arose from the discovery of a novel tridecapeptide from bovine peripheral blood granulocytes. The purified peptides and their carboxamide analogs have potent antibacterial, antiviral, antiprotozoal, and antifungal activities. These peptides, designated BGP-A and MGP-A, are effective compounds for use in human and/or veterinary medicine, or as agents in agricultural, food science, or industrial applications for example.
The details of the preferred embodiment of the present invention are set forth in the accompanying drawings and the description below. Once the details of the invention are known, numerous additional innovations and changes will become obvious to one skilled in the art.